How fuel cost is calculated
Everything is converted to kilometres and litres first. Fuel used is the distance times litres per kilometre, and the cost is that many litres times the price per litre. Prices per gallon are converted using 3.785 litres for a US gallon and 4.546 litres for a UK gallon.
Save on fuel
- Keep tyres at the right pressure and remove roof racks you do not use.
- Drive smoothly. Hard acceleration and braking waste fuel.
- Planning a longer journey with hotels and food? Use the trip cost planner, or check your pace and arrival time with the speed and pace calculator.
Frequently asked questions
How do I calculate fuel cost for a trip?
Divide the distance by your fuel economy to get the fuel used, then multiply by the price per litre. 100 km at 10 km per litre uses 10 litres, and at 300 per litre costs 3,000.
How do I convert L/100km to km per litre?
Divide 100 by the L/100km figure. A car using 8 L/100km does 12.5 km per litre. To go the other way divide 100 by the km per litre.
What is the difference between US and UK mpg?
A UK (imperial) gallon is 4.546 litres and a US gallon is 3.785 litres, so the same car gets a higher mpg figure in the UK. Pick the one your car's manual or dashboard uses.
Why is my real fuel use higher than the manual says?
City traffic, air conditioning, heavy loads, high speed and low tyre pressure all raise fuel use. Use the average from your own last few tanks for the best estimate.
Can I use it for electric cars?
No, this is for petrol, diesel and gas. For an electric car, work out the kWh used and multiply by your electricity price.